/Engine/Source/Developer/AssetTools/Public/AssetTypeActions_Base.h
Returns thumbnail brush unique for the given asset data. Returning null falls back to class thumbnail brush.
virtual const [FSlateBrush](API\Runtime\SlateCore\Styling\FSlateBrush) * GetThumbnailBrush ( const [FAssetData](API\Runtime\CoreUObject\AssetRegistry\FAssetData) & InAssetData, const [FName](API\Runtime\Core\UObject\FName) InClassName ) const